Determining the availability of a radio access technology

ABSTRACT

In systems and methods of determining the availability of a radio access technology, a first message is received from a wireless device in communication with an access node using a first radio access technology, wherein the first message comprises a request of the availability of a second radio access technology at the access node. Based on the first message, an identifier of the wireless device and an identifier of the first access node are determined. Based on the access node identifier, it is identified whether the second radio access technology is available at the access node, and a second message is sent to the wireless device instructing the wireless device to scan for the second radio access technology when it is available.

This patent application is a continuation of U.S. patent applicationSer. No. 14/051,412, filed on Oct. 10, 2013, entitled DETERMINING THEAVAILABILITY OF A RADIO ACCESS TECHNOLOGY.

TECHNICAL BACKGROUND

Where a wireless communication system supports two or more radio accesstechnologies, a wireless device can be configured to detect the networkpresence of each radio access technology and determine which technologyto use for network communication. However, a wireless device can becaused to perform unnecessary scanning for radio access technologieseven where one or more radio access technologies are not available, forexample, because of limited coverage of a radio access technology.Scanning for a radio access technology which is not available within thelimits of detection of the wireless device can cause network entry delayand can unnecessarily deplete battery power of the wireless device.

Overview

In operation, a first message is received from a wireless device incommunication with an access node, where the wireless device uses afirst radio access technology, and the message comprises a request ofthe availability of a second radio access technology at the access node.Based on the first message, an identifier of the wireless device and anidentifier of the first access node are determined. Based on the accessnode identifier, it is identified that the second radio accesstechnology is available at the access node, and a second message is sentto the wireless device instructing the wireless device to scan for thesecond radio access technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary communication system to determine theavailability of a radio access technology.

FIG. 2 illustrates an exemplary method of determining the availabilityof a radio access technology.

FIG. 3 illustrates another exemplary method of determining theavailability of a radio access technology.

FIG. 4 illustrates another exemplary method of determining theavailability of a radio access technology.

FIG. 5 illustrates another exemplary communication system to determinethe availability of a radio access technology.

FIG. 6 illustrates another exemplary method of determining theavailability of a radio access technology.

FIG. 7 illustrates an exemplary processing node.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary communication system 100 to determinethe availability of a radio access technology comprising wireless device102, access node 104, communication network 106, and processing node108. Examples of wireless device 102 can comprise a cell phone, a smartphone, a computing platform such as a laptop, palmtop, or tablet, apersonal digital assistant, or an internet access device, includingcombinations thereof. Wireless device 102 is in communication withaccess node 104 over communication link 110.

Access node 104 is a network node capable of providing wirelesscommunications to wireless device 102, and can be, for example, a basetransceiver station, a radio base station, an eNodeB device, or anenhanced eNodeB device. Access node 104 can comprise a coverage areawhich can be divided into two or more portions or sectors, illustratedin FIG. 1 as sectors 104A, 104B, and 104C. Each sector can comprisemultiple carrier bands, and can also comprise two or more radio accesstechnologies, from access node 104. Access node 104 is in communicationwith communication network 106 over communication link 112.

Communication network 106 can be a wired and/or wireless communicationnetwork, and can comprise processing nodes, routers, gateways, andphysical and/or wireless data links for carrying data among variousnetwork elements, including combinations thereof, and can include alocal area network, a wide area network, and an internetwork (includingthe Internet). Communication network 106 can be capable of carryingvoice information and other data, for example, to support communicationsby a wireless device such as wireless device 102. Wireless networkprotocols may comprise code division multiple access (CDMA) 1×RTT,Global System for Mobile communications (GSM), Universal MobileTelecommunications System (UMTS), High-Speed Packet Access (HSPA),Evolution Data Optimized (EV-DO), EV-DO rev. A, WorldwideInteroperability for Microwave Access (WiMAX), and Third GenerationPartnership Project Long Term Evolution (3GPP LTE). Wired networkprotocols that may be utilized by communication network 106 compriseEthernet, Fast Ethernet, Gigabit Ethernet, Local Talk (such as CarrierSense Multiple Access with Collision Avoidance), Token Ring, FiberDistributed Data Interface (FDDI), and Asynchronous Transfer Mode (ATM).Communication network 106 may also comprise a wireless network,including base stations, wireless communication nodes, telephonyswitches, internet routers, network gateways, computer systems,communication links, or some other type of communication equipment, andcombinations thereof.

Processing node 108 can comprise a processor and associated circuitry toexecute or direct the execution of computer-readable instructions, andcan be configured to determining the availability of a radio accesstechnology at access node 104. Processing node 108 can retrieve andexecute software from storage, which can include a disk drive, flashdrive, memory circuitry, or some other memory device, and which can belocal or remotely accessible. The software comprises computer programs,firmware, or some other form of machine-readable instructions, and mayinclude an operating system, utilities, drivers, network interfaces,applications, or some other type of software, including combinationsthereof. Processing node 108 can receive instructions and other input ata user interface. Examples of processing node 108 can comprise astandalone computing device, a computer system, or a network component,such as an access service network gateway (ASN-GW), a packet datanetwork gateway (P-GW), a serving gateway (S-GW), a mobile switchingcontroller (MSC), a packet data serving node (PDSN), call processingequipment, a home agent, a radio node controller (RNC), a subscriberprofile system (SPS), authentication, authorization, and accounting(AAA) equipment, a controller node such as a mobile switching center(MSC), a dispatch call controller (DCC), a mobility management entity(MME), or other similar network node, including combinations thereof.Processing node 108 is in communication with communication network 106over communication link 114.

Communication links 110, 112, and 114 can be wired or wirelesscommunication links. Wired communication links can comprise, forexample, twisted pair cable, coaxial cable or fiber optic cable, orcombinations thereof. Wireless communication links can comprise a radiofrequency, microwave, infrared, or other similar signal, and can use asuitable communication protocol, for example, Global System for Mobiletelecommunications (GSM), Code Division Multiple Access (CDMA),Worldwide Interoperability for Microwave Access (WiMAX), or Long TermEvolution (LTE), or combinations thereof. Other wireless protocols canalso be used.

Other network elements may be present in communication system 100 tofacilitate wireless communication but are omitted for clarity, such asbase stations, base station controllers, gateways, mobile switchingcenters, dispatch application processors, and location registers such asa home location register or visitor location register. Furthermore,other network elements may be present to facilitate communicationbetween access node 104, communication network 106, and processing node108 which are omitted for clarity, including additional processingnodes, routers, gateways, and physical and/or wireless data links forcarrying data among the various network elements.

In a wireless communication network which uses two or more radio accesstechnologies, a wireless device can be enabled to detect a presence ofeach radio access technology. Further, a network element of the system,such as a processing node or the wireless device, can be enabled todetermine which radio access technology to select for wirelesscommunications. For example, wireless device 102 can be enabled to scanfor the presence of radio access technologies. Also, coverageinformation of each radio access technology (including coverage holes ofeach radio access technology) of the communication system can beprovided and stored on wireless device 102, and the coverage informationcan be used to trigger wireless device 102 to scan for available radioaccess technologies. However, a wireless device may scan for a certainradio access technology even when that radio access technology is notavailable or detectable by the wireless device, which can cause delay inestablishing network communication with wireless device 102, and mayfurther unnecessarily drain a battery of wireless device 102. Thenegative effects on wireless device 102 are exacerbated in a case wherecommunication system 100 includes a radio access technology which isboth desirable and is not fully or uniformly deployed in communicationsystem 100.

In operation, a first message is received from wireless device 102,which is in communication with access node 104 using a first radioaccess technology. The first message requests an availability of asecond radio access technology at access node 104. The first message canbe received from wireless device 102 at access node 104, or atprocessing node 108, or at another network element of communicationsystem 100. Based on the first message, an identifier of wireless device102 and of access node 104 can be determined. Based on the access nodeidentifier it can be determined that the second radio access technologyis available at the access node. It can further be determined based onthe wireless device identifier that wireless device 102 is capable ofusing the second radio access technology. When the second radio accesstechnology is available at access node 104, and when wireless device 102is capable of using the second radio access technology, a second messageis sent to wireless device 102 instructing wireless device 102 to scanfor the second radio access technology. The second message can be sentfrom access node 104 at the direction of processing node 108, or accessnode 104 can make the above-described determinations and send the secondmessage to wireless device 102.

FIG. 2 illustrates an exemplary method of determining the availabilityof a radio access technology. A first message is received from awireless device requesting an availability of a second radio accesstechnology at the access node. For example, wireless device 102 cancommunicate with access node 104 using a first radio access technology,and wireless device 102 can send a message to access node 104 todetermine whether a second radio access technology is available ataccess node 104. Communication system 100 can be a multi-technologycommunication system in which two or more radio access technologies areprovided by the communication system.

However, every radio access technology of the communication system maynot be available at every access node, owing to the age of the equipmentat an access node, or the expense of deploying a certain radio accesstechnology at the access node, or because the access node has node yetbeen configured to use the radio access technology, or because abackhaul link between the access node the communication system cannothandle requirements of a certain radio access technology, and the like.To begin to determine the availability of the second radio accesstechnology at access node 104, wireless device 102 may send a firstmessage. In an embodiment, the second radio access technology cancomprise a lower latency or higher speed radio access technology thanthe first radio access technology. For example, the first radio accesstechnology can comprise CDMA, W-CDMA, GSM, eHRPD (evolved high ratepacket data), and the like, the second radio access technology cancomprise LTE, LTE Advanced, WiMAX, or another so-called 4G radio accesstechnology. The first message can be received at access node 104, andcan be processed at processing node 108, or at access node 104, or atanother network element of communication system 100. The first messagecan comprise an explicit request for the availability of the secondradio access technology, or it can comprise a message as simple as a“ping” or other short message directed at a network element (such asprocessing node 108). Further, processing node 108 (or another networkelement) can be configured to respond to the explicit request, the“ping”, or another similar message.

Based on the first message, an identifier of the wireless device and anidentifier of the first access node are determined (operation 204). Theidentifier of the wireless device can comprise a unique identifier ofthe wireless device which indicates the capabilities of the wirelessdevice to use one or more radio access technologies. Additionally, oralternatively, the wireless device identifier can be used by processingnode 108 (or another network element of communication system 100) todetermine whether wireless device 102 is authorized to use the secondradio access technology. When wireless device 102 is not authorized touse the second radio access technology, a message indicating the lack ofauthorization can be sent to the wireless device. The identifier of thefirst access node can comprise a unique identifier of the access nodewhich indicates the capabilities of the access node, including the radioaccess technologies available at the access node.

Based on the access node identifier, it is identified that the secondradio access technology is available at the access node (operation 206).The identification that the second radio access technology is availableat access node 104 can be made at processing node 108, at access node104, or at another network element of communication system 100.Subsequently, a second message is sent to the wireless deviceinstructing the wireless device to scan for the second radio accesstechnology (operation 208). When wireless device 102 receives the secondmessage, wireless device 102 may then scan for available signals fromaccess node 104 using the second radio access technology.

FIG. 3 illustrates another exemplary method of determining theavailability of a radio access technology. In operation 302, acommunication session is established between a wireless device and anaccess node using a first radio access technology. For example, wirelessdevice 102 can perform initial synchronization and network entryprocesses with access node 104 and a communication session can beestablished between wireless device 102 and access node 104 using afirst radio access technology.

In addition, the wireless device can be prevented from scanning for asecond radio access technology (operation 304). For example, wirelessdevice 102 can be prevented by instructions on wireless device 102 fromscanning for the second radio access technology. Additionally, oralternatively, a message can be sent to wireless device 102 to instructit not to scan for the second radio access technology by access node104, or by processing node 108, or by another network element ofcommunication system 100. In an embodiment, wireless device 102 can beinstructed (or can execute instructions) to prevent scanning for thesecond radio access technology when wireless device 102 uses the firstradio access technology.

When the communication session is established between the wirelessdevice and the access node, a message is received from the wirelessdevice requesting an availability of a second radio access technology atthe access node (operation 306). For example, wireless device 102 cancommunicate with access node 104 using the first radio accesstechnology, and wireless device 102 can send a message to access node104 to determine whether a second radio access technology is availableat access node 104. Communication system 100 can be a multi-technologycommunication system in which two or more radio access technologies areprovided by the communication system. In an embodiment, the second radioaccess technology can comprise a lower latency or higher speed radioaccess technology than the first radio access technology. For example,the first radio access technology can comprise CDMA, W-CDMA, GSM, eHRPD(evolved high rate packet data), and the like, the second radio accesstechnology can comprise LTE, LTE Advanced, WiMAX, or another so-called4G radio access technology. The first message can be received at accessnode 104, and can be processed at processing node 108, or at access node104, or at another network element of communication system 100. In somecases, the first radio access technology can be associated with a firstcommunication network and the second radio access technology can beassociated with a second communication network. In an embodiment,message is received from the wireless device when the wireless deviceestablishes a data communication session with the access node using thefirst radio access technology to send the message.

Based on the message from the wireless device, an identifier of thewireless device, an identifier of the first access node, and a sector ofthe access node with which the wireless device is in communication aredetermined (operation 308). The identifier of the wireless device cancomprise a unique identifier of the wireless device which indicates thecapabilities of the wireless device to use one or more radio accesstechnologies. Additionally, or alternatively, the wireless deviceidentifier can be used by processing node 108 (or another networkelement of communication system 100) to determine whether wirelessdevice 102 is authorized to use the second radio access technology. Whenwireless device 102 is not authorized to use the second radio accesstechnology, a message indicating the lack of authorization can be sentto the wireless device. The identifier of the first access node cancomprise a unique identifier of the access node which indicates thecapabilities of the access node, including the radio access technologiesavailable at the access node. The sector identifier can indicate whichof sectors 104A, 104B, and 104C wireless device 102 is in communicationwith. In an embodiment, the second radio access technology may beavailable in less than all of the sectors of access node 104.Additionally, or alternatively, the sector identifier can be used todetermine a loading of a channel in the identified sector which uses thesecond radio access technology, and the determined loading may affectthe availability of the second radio access technology.

Based on the access node identifier and the access node sectoridentifier, it is identified that the second radio access technology isavailable at the access node (operation 310). The identification thatthe second radio access technology is available at access node 104 canbe made at processing node 108, at access node 104, or at anothernetwork element of communication system 100. Subsequently, a message issent to the wireless device instructing the wireless device to scan forthe second radio access technology (operation 312). When wireless device102 receives the second message, wireless device 102 may then scan foravailable signals from access node 104 using the second radio accesstechnology. In an embodiment, wireless device 102 is prevented fromscanning for the second access technology until the second message issent instructing the wireless device to scan for the second radio accesstechnology.

FIG. 4 illustrates another exemplary method of determining theavailability of a radio access technology. In operation 402, acommunication session is established between a wireless device and anaccess node using a first radio access technology. For example, wirelessdevice 102 can perform initial synchronization and network entryprocesses with access node 104 and a communication session can beestablished between wireless device 102 and access node 104 using afirst radio access technology. Additionally, the wireless device can beprevented from scanning for a second radio access technology (operation404). For example, wireless device 102 can be prevented by instructionson wireless device 102 from scanning for the second radio accesstechnology. Additionally, or alternatively, a message can be sent towireless device 102 to instruct it not to scan for the second radioaccess technology by access node 104, or by processing node 108, or byanother network element of communication system 100.

When the communication session is established between the wirelessdevice and the access node, a message is received from the wirelessdevice requesting an availability of a second radio access technology atthe access node (operation 406). For example, wireless device 102 cancommunicate with access node 104 using the first radio accesstechnology, and wireless device 102 can send a message to access node104 to determine whether a second radio access technology is availableat access node 104. The message can also be received at processing node108. Communication system 100 can be a multi-technology communicationsystem in which two or more radio access technologies are provided bythe communication system. In an embodiment, the second radio accesstechnology can comprise a lower latency or higher speed radio accesstechnology than the first radio access technology. For example, thefirst radio access technology can comprise CDMA, W-CDMA, GSM, eHRPD(evolved high rate packet data), and the like, the second radio accesstechnology can comprise LTE, LTE Advanced, WiMAX, or another so-called4G radio access technology. The first message can be received at accessnode 104, and can be processed at processing node 108, or at access node104, or at another network element of communication system 100. In somecases, the first radio access technology can be associated with a firstcommunication network and the second radio access technology can beassociated with a second communication network. In an embodiment,message is received from the wireless device when the wireless deviceestablishes a data communication session with the access node using thefirst radio access technology to send the message.

Based on the message from the wireless device, an identifier of thewireless device, an identifier of the first access node, and a sector ofthe access node with which the wireless device is in communication aredetermined (operation 408). The identifier of the wireless device cancomprise a unique identifier of the wireless device which indicates thecapabilities of the wireless device to use one or more radio accesstechnologies. Additionally, or alternatively, the wireless deviceidentifier can be used by processing node 108 (or another networkelement of communication system 100) to determine whether wirelessdevice 102 is authorized to use the second radio access technology. Whenwireless device 102 is not authorized to use the second radio accesstechnology, a message indicating the lack of authorization can be sentto the wireless device. The identifier of the first access node cancomprise a unique identifier of the access node which indicates thecapabilities of the access node, including the radio access technologiesavailable at the access node. The sector identifier can indicate whichof sectors 104A, 104B, and 104C wireless device 102 is in communicationwith. In an embodiment, the second radio access technology may beavailable in less than all of the sectors of access node 104.Additionally, or alternatively, the sector identifier can be used todetermine a loading of a channel in the identified sector which uses thesecond radio access technology, and the determined loading may affectthe availability of the second radio access technology.

Based on the access node identifier and the access node sectoridentifier it is determined whether the second radio access technologyis available at the access node (operation 410). The identification thatthe second radio access technology is available at access node 104 canbe made at processing node 108, at access node 104, or at anothernetwork element of communication system 100. When the second radioaccess is available access node 104 (operation 410-Y), a message is sentto wireless device 102 instructing wireless device 102 to scan for thesecond radio access technology (operation 412). For example, wirelessdevice 102 can be instructed to scan for a carrier band using the secondradio access technology, or wireless device 102 can be instructed toscan for some other indication that a carrier using the second radioaccess technology is available at access node 104. In another example,the second message instructs the wireless device to scan for the secondradio access technology while maintaining communication with the accessnode using the first radio access technology. The maintainedcommunication can be a data communication session using the first radioaccess technology.

When the second radio access technology is not available at access node104 (operation 410-N), an indication is sent to wireless device 102 thatthe second radio access technology is not available (operation 414). Theindication can comprise an instruction preventing wireless device 102from scanning for the second access technology. Additionally, oralternatively, the indication can trigger instructions on wirelessdevice 102 which prevent the wireless device from scanning for thesecond radio access technology.

The message instructing wireless device 102 to scan for the second radioaccess technology, or indicating that the second radio access technologyis not available, can be sent after a predetermined period of time froma time that the message requesting an availability of a second radioaccess technology is received. Further, the predetermined period of timecan be selected so as to convey additional information to wirelessdevice 102. For example, a message size of the message from wirelessdevice 102 requesting availability of the second radio accesstechnology, or of the message indicating the availability of the secondradio access technology (from, e.g., processing node 510), or of bothmessages, can be reduced to decrease network load or network congestionwhich may be caused by the messages. In an embodiment, a small-sizedmessage (such as a “ping” message or other similar message) sent bywireless device 102 can be directed to a particular network location,such as an interface of processing node 108. In response, the messagesent by processing node 108 can be similarly small-sized, and can besent to wireless device 102 after a predetermined period of timefollowing the receipt of the message from wireless device 102.

As described above, the predetermined time can be selected to conveyavailability of the second radio access technology. For example, thesecond message can be sent at a first predetermined time after the firstmessage is received to indicate that the second radio access technologyis not present at the access node. Also, the second message can be sentat a second predetermined time after the first message is received toindicate that a channel using the second radio access technology at theaccess node cannot accept the wireless device, for example, because acongestion level of the channel meets a congestion level threshold.Additionally, the second message can be sent at a third predeterminedtime after the first message is received to indicate that the secondradio access technology is not available at the access node nor at aneighbor access node. Further, the second message can be sent at afourth predetermined time after the first message is received toindicate that the second radio access technology is not available at theaccess node nor at second access nodes within a predetermined radius ofthe access node. Other possible predetermined times associated withother information are also possible, including combinations of theforegoing.

The predetermined times can further be selected based on the first radioaccess technology. For example, the predetermined times can be selectedto reflect the latency, or ability to convey data, of a specific radioaccess technology. In an embodiment, a first set of predetermined timescan be used where, for example, the first radio access technologycomprises CDMA, and a second set of predetermined times can be usedwhere, for example, the first radio access technology comprises LTE. Thepredetermined times can be increased based on a determined level ofnetwork congestion or resource utilization.

The indication to the wireless device that the second radio accesstechnology is not available can also comprise an instruction to sendanother message requesting the availability of the second radio accesstechnology at a future time. The future time can comprise a time after apredetermined duration, or it can comprise a time when the wirelessdevice enters a new sector of the access node, or when the wirelessdevice enters a sector of second access node. The future time can alsobe a plurality of future times, such that the wireless device requeststhe availability of the second radio access node periodically. Otherfuture times are also possible, as well as combinations of theforegoing.

FIG. 5 illustrates another exemplary communication system 500 todetermine the availability of a radio access technology comprisingwireless device 502, access node 504, access node 506, communicationnetwork 508, and processing node 510. Examples of wireless device 502can comprise a cell phone, a smart phone, a computing platform such as alaptop, palmtop, or tablet, a personal digital assistant, or an internetaccess device, including combinations thereof. Wireless device 502 cancommunicate with access node 504 over communication link 512, and withaccess node 506 over communication link 514.

Access nodes 504 and 506 are each a network node capable of providingwireless communications to wireless device 502, and can be, for example,a base transceiver station, a radio base station, an eNodeB device, oran enhanced eNodeB device. Access node 504 is in communication withcommunication network 508 over communication link 516, and access node506 is in communication with communication network 508 overcommunication link 518. Access nodes 504 and 506 can communicate witheach other over communication link 520.

Communication network 508 can be a wired and/or wireless communicationnetwork, and can comprise processing nodes, routers, gateways, andphysical and/or wireless data links for carrying data among variousnetwork elements, including combinations thereof, and can include alocal area network, a wide area network, and an internetwork (includingthe Internet). Communication network 508 can be capable of carryingvoice information and other data, for example, to support communicationsby a wireless device such as wireless device 502. Wireless networkprotocols may comprise code division multiple access (CDMA) 1×RTT,Global System for Mobile communications (GSM), Universal MobileTelecommunications System (UMTS), High-Speed Packet Access (HSPA),Evolution Data Optimized (EV-DO), EV-DO rev. A, WorldwideInteroperability for Microwave Access (WiMAX), and Third GenerationPartnership Project Long Term Evolution (3GPP LTE). Wired networkprotocols that may be utilized by communication network 508 compriseEthernet, Fast Ethernet, Gigabit Ethernet, Local Talk (such as CarrierSense Multiple Access with Collision Avoidance), Token Ring, FiberDistributed Data Interface (FDDI), and Asynchronous Transfer Mode (ATM).Communication network 508 may also comprise a wireless network,including base stations, wireless communication nodes, telephonyswitches, internet routers, network gateways, computer systems,communication links, or some other type of communication equipment, andcombinations thereof.

Processing node 510 can comprise a processor and associated circuitry toexecute or direct the execution of computer-readable instructions, andcan be configured to determining the availability of a radio accesstechnology at access nodes 504 and 506. Processing node 510 can retrieveand execute software from storage, which can include a disk drive, flashdrive, memory circuitry, or some other memory device, and which can belocal or remotely accessible. The software comprises computer programs,firmware, or some other form of machine-readable instructions, and mayinclude an operating system, utilities, drivers, network interfaces,applications, or some other type of software, including combinationsthereof. Processing node 510 can receive instructions and other input ata user interface. Examples of processing node 510 can comprise astandalone computing device, a computer system, or a network component,such as an access service network gateway (ASN-GW), a packet datanetwork gateway (P-GW), a serving gateway (S-GW), a mobile switchingcontroller (MSC), a packet data serving node (PDSN), call processingequipment, a home agent, a radio node controller (RNC), a subscriberprofile system (SPS), authentication, authorization, and accounting(AAA) equipment, a controller node such as a mobile switching center(MSC), a dispatch call controller (DCC), a mobility management entity(MME), or other similar network node, including combinations thereof.Processing node 510 is in communication with communication network 508over communication link 522.

Communication links 512, 514, 516, 518, 520 and 522 can be wired orwireless communication links. Wired communication links can comprise,for example, twisted pair cable, coaxial cable or fiber optic cable, orcombinations thereof. Wireless communication links can comprise a radiofrequency, microwave, infrared, or other similar signal, and can use asuitable communication protocol, for example, Global System for Mobiletelecommunications (GSM), Code Division Multiple Access (CDMA),Worldwide Interoperability for Microwave Access (WiMAX), or Long TermEvolution (LTE), or combinations thereof. Other wireless protocols canalso be used.

Other network elements may be present in communication system 500 tofacilitate wireless communication but are omitted for clarity, such asbase stations, base station controllers, gateways, mobile switchingcenters, dispatch application processors, and location registers such asa home location register or visitor location register. Furthermore,other network elements may be present to facilitate communicationbetween access nodes 504 and 506, communication network 508, andprocessing node 510 which are omitted for clarity, including additionalprocessing nodes, routers, gateways, and physical and/or wireless datalinks for carrying data among the various network elements.

FIG. 6 illustrates another exemplary method of determining theavailability of a radio access technology. A communication session isestablished between a wireless device and an access node using a firstradio access technology (operation 602). For example, wireless device502 can perform initial synchronization and network entry processes withaccess node 504 and a communication session can be established betweenwireless device 502 and access node 504 using a first radio accesstechnology. Additionally, the wireless device can be prevented fromscanning for a second radio access technology (operation 604). Forexample, wireless device 502 can be prevented by instructions onwireless device 502 from scanning for the second radio accesstechnology. Additionally, or alternatively, a message can be sent towireless device 502 to instruct it not to scan for the second radioaccess technology by access node 504, or by processing node 510, or byanother network element of communication system 500.

When the communication session is established between the wirelessdevice and the access node, a message is received from the wirelessdevice requesting an availability of a second radio access technology atthe access node (operation 606). For example, wireless device 502 cancommunicate with access node 504 using the first radio accesstechnology, and wireless device 502 can send a message to access node504 to determine whether a second radio access technology is availableat access node 504. Communication system 500 can be a multi-technologycommunication system in which two or more radio access technologies areprovided by the communication system. In an embodiment, the second radioaccess technology can comprise a lower latency or higher speed radioaccess technology than the first radio access technology. For example,the first radio access technology can comprise CDMA, W-CDMA, GSM, eHRPD(evolved high rate packet data), and the like, the second radio accesstechnology can comprise LTE, LTE Advanced, WiMAX, or another so-called4G radio access technology. The first message can be received at accessnode 504, and can be processed at processing node 510, or at access node504, or at another network element of communication system 500. In somecases, the first radio access technology can be associated with a firstcommunication network and the second radio access technology can beassociated with a second communication network. In an embodiment,message is received from the wireless device when the wireless deviceestablishes a data communication session with the access node using thefirst radio access technology to send the message.

Based on the message from the wireless device, an identifier of thewireless device and an identifier of the first access node aredetermined (operation 608). The identifier of the wireless device cancomprise a unique identifier of the wireless device which indicates thecapabilities of the wireless device to use one or more radio accesstechnologies. Additionally, or alternatively, the wireless deviceidentifier can be used by processing node 510 (or another networkelement of communication system 500) to determine whether wirelessdevice 502 is authorized to use the second radio access technology. Whenwireless device 502 is not authorized to use the second radio accesstechnology, a message indicating the lack of authorization can be sentto the wireless device. The identifier of the first access node cancomprise a unique identifier of the access node which indicates thecapabilities of the access node, including the radio access technologiesavailable at the access node.

Based on the access node identifier and the access node sectoridentifier it is identified whether the second radio access technologyis available at a second access node (operation 610). The identificationthat the second radio access technology is available at, for example,access node 506, can be made at processing node 510, at access node 504,or at another network element of communication system 500. When thesecond radio access is available at access node 506, a message is sentto wireless device 502 indicating that the second radio accesstechnology is available at second access node 506 (operation 612). Theindication can also comprise an instruction for wireless device 502 toscan for the second radio access technology.

When the second radio access technology is detected at wireless device502, a handover is performed to change wireless device 502 fromcommunicating with access node 504 using the first radio accesstechnology to communicating with access node 506 using the second radioaccess technology (operation 614).

FIG. 7 illustrates an exemplary processing node 700 in a communicationsystem. Processing node 700 comprises communication interface 702, userinterface 704, and processing system 706 in communication withcommunication interface 702 and user interface 704. Processing node 700can be configured to determine the availability of a radio accesstechnology. Processing system 706 includes storage 708, which cancomprise a disk drive, flash drive, memory circuitry, or other memorydevice. Storage 708 can store software 710 which is used in theoperation of the processing node 700. Storage 708 may include a diskdrive, flash drive, data storage circuitry, or some other memoryapparatus. Software 710 may include computer programs, firmware, or someother form of machine-readable instructions, including an operatingsystem, utilities, drivers, network interfaces, applications, or someother type of software. Processing system 706 may include amicroprocessor and other circuitry to retrieve and execute software 710from storage 708. Processing node 700 may further include othercomponents such as a power management unit, a control interface unit,etc., which are omitted for clarity. Communication interface 702 permitsprocessing node 700 to communicate with other network elements. Userinterface 704 permits the configuration and control of the operation ofprocessing node 700.

Examples of processing node 700 include access node 104, processing node108, access nodes 504 and 506, and processing node 510. Processing node700 can be an adjunct or component of a network element. Processing node700 can also be another network element in a communication system.Further, the functionality of processing node 700 can be distributedover two or more network elements of a communication system.

The exemplary systems and methods described herein can be performedunder the control of a processing system executing computer-readablecodes embodied on a computer-readable recording medium or communicationsignals transmitted through a transitory medium. The computer-readablerecording medium is any data storage device that can store data readableby a processing system, and includes both volatile and nonvolatilemedia, removable and non-removable media, and contemplates mediareadable by a database, a computer, and various other network devices.

Examples of the computer-readable recording medium include, but are notlimited to, read-only memory (ROM), random-access memory (RAM), erasableelectrically programmable ROM (EEPROM), flash memory or other memorytechnology, holographic media or other optical disc storage, magneticstorage including magnetic tape and magnetic disk, and solid statestorage devices. The computer-readable recording medium can also bedistributed over network-coupled computer systems so that thecomputer-readable code is stored and executed in a distributed fashion.The communication signals transmitted through a transitory medium mayinclude, for example, modulated signals transmitted through wired orwireless transmission paths.

The above description and associated figures teach the best mode of theinvention. The following claims specify the scope of the invention. Notethat some aspects of the best mode may not fall within the scope of theinvention as specified by the claims. Those skilled in the art willappreciate that the features described above can be combined in variousways to form multiple variations of the invention, and that variousmodifications may be made to the configuration and methodology of theexemplary embodiments disclosed herein without departing from the scopeof the present teachings. Those skilled in the art also will appreciatethat various features disclosed with respect to one exemplary embodimentherein may be used in combination with other exemplary embodiments withappropriate modifications, even if such combinations are not explicitlydisclosed herein. As a result, the invention is not limited to thespecific embodiments described above, but only by the following claimsand their equivalents.

What is claimed is:
 1. A system of determining the availability of aradio access technology, the system comprising: a processing nodecomprising a processor, wherein the processing node is configured to:receive a first message from a wireless device in communication with anaccess node using a first radio access technology to request anavailability of a second radio access technology at the access node;determine based on the first message an identifier of the wirelessdevice and an identifier of the access node; identify based on theaccess node identifier that the second radio access technology isavailable at the access node; and send to the wireless device a secondmessage instructing the wireless device to scan for the second radioaccess technology.
 2. The system of claim 1, wherein the first radioaccess technology is associated with a first communication network andthe second radio access technology is associated with a secondcommunication network.
 3. The system of claim 1, wherein the processingnode is further configured to prevent the wireless device from scanningfor the second radio access technology until the second message is sentinstructing the wireless device to scan for the second radio accesstechnology.
 4. The system of claim 1, wherein the second messageinstructs the wireless device to scan for the second radio accesstechnology while maintaining communication with the access node usingthe first radio access technology.
 5. The system of claim 1, wherein thefirst message is received from the wireless device when the wirelessdevice establishes a data communication session with the access nodeusing the first radio access technology to send the message.
 6. Thesystem of claim 1, wherein the processing node is further configured todetermine based on the first message a sector of the access node withwhich the wireless device is in communication with the access node. 7.The system of claim 6, wherein the processing node is further configuredto identify based on the sector of the access node that the second radioaccess technology is available at the access node.
 8. A system ofdetermining the availability of a radio access technology, comprising: aprocessing node comprising a processor, wherein the processing node isconfigured to: receive a first message from a wireless device incommunication with an access node using a first radio access technologyto request information about an availability of a second radio accesstechnology at the access node; determine based on the message anidentifier of the wireless device and an identifier of the access node;identify based on the access node identifier whether the second radioaccess technology is available at the access node; send to the wirelessdevice a second message instructing the wireless device to scan for thesecond radio access technology when it is identified that the secondradio access technology is available at the access node; and indicate tothe wireless device a message that the second radio access technology isnot available at the access node when it is identified that the secondradio access technology is not available at the access node.
 9. Thesystem of claim 8, wherein indicating to the wireless device that thesecond radio access technology is not available at the access nodefurther comprises instructing the wireless device to send a secondmessage to request the availability of the second radio accesstechnology at an indicated future time.
 10. The system of claim 9,wherein the future time is one of when the wireless device enters a newsector of the access node, when the wireless device enters a sector ofthe second access node, and after a predetermined duration.
 11. Thesystem of claim 8, wherein indicating to the wireless device that thesecond radio access technology is not available at the access nodefurther comprises sending the second message at a first predeterminedtime after the first message is received to indicate that the secondradio access technology is not present at the access node.
 12. Thesystem of claim 11, wherein the first delay time and the second delaytime are determined based on the first radio access technology.
 13. Thesystem of claim 8, wherein indicating to the wireless device that thesecond radio access technology is not available at the access nodefurther comprises sending the second message at a second predeterminedtime after the first message is received to indicate that a channelusing the second radio access technology at the access node cannotaccept the wireless device.
 14. The system of claim 8, whereinindicating to the wireless device that the second radio accesstechnology is not available at the access node further comprises sendingthe second message at a third predetermined time after the first messageis received to indicate that the second radio access technology is notavailable at the access node nor at a neighbor access node.
 15. Thesystem of claim 8, wherein indicating to the wireless device that thesecond radio access technology is not available at the access nodefurther comprises sending the second message at a fourth predeterminedtime after the first message is received to indicate that the secondradio access technology is not available at the access node nor atsecond access nodes within a predetermined radius of the access node.16. The system of claim 8, wherein the processing node is furtherconfigured to: determine based on the wireless device identifier and theaccess node identifier that the access node is associated with adifferent communication network than the wireless device; and indicateto the wireless device that the second radio access technology is notavailable at the access node.